Structural origin of hardness decrease in irradiated sodium borosilicate glass

W Yuan and HB Peng and ML Sun and X Du and P Lv and Y Zhao and FF Liu and BT Zhang and XY Zhang and L Chen and TS Wang, JOURNAL OF CHEMICAL PHYSICS, 147, 234502 (2017).

DOI: 10.1063/1.5004220

Mechanical properties such as hardness and modulus of sodium borosilicate (NBS) glasses in irradiation conditions were studied extensively in recent years. With irradiation of heavy ions, a trend that the hardness of NBS glasses decreased and then stabilized with increase of dose has been reported. Variations in network structures were suggested for the decrease of hardness after irradiation. However, details of these variations in a network of glass are not clear yet. In this paper, molecular dynamics was applied to simulate the network variations in a type of NBS glass and the changes in hardness after xenon irradiation. The simulation results indicated that hardness variation decreased with fiuence in an exponential law, which was consistent with experimental results. The origin of hardness decrease after irradiation might be attributed to the break of B-IV-O links that could be derived from the (1) decrease of average coordinate number of boron, (2) decrease of Si-O-B-IV bonds, and (3) increase of non-bridging oxygen. Published by AIP Publishing.

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